Unilateral vs Bilateral Cages in Lumbar Interbody Fusions: A Meta-Analysis of Clinical and Radiographic Outcomes.

Background Bilateral cages are often used for interbody fusion. However, this procedure may not be possible in some cases making unilateral cages a reasonable alternative. The literature remains divided on the clinical and radiological distinctions when comparing unilateral to bilateral cages in lumbar interbody fusion. Thus, this meta-analysis will analyze the clinical and radiographic outcomes between these two groups. Methods PubMed, Cochrane, and Google Scholar (page 1-20) were searched till January 2024. The clinical outcomes evaluated were the incidence of adverse events, surgery-related parameters, and patient reported outcomes. Results Lower rates of pseudoarthrosis, subsidence, were reported in the bilateral cages group (p=0.01, p=0.001, respectively) whereas shorter operative time (OR time), and lower estimated blood loss (EBL) were seen in unilateral cage group (p<0.001, and p=0.003). There was no statistically significant difference in the remaining analyzed outcomes. Conclusion Unilateral cages were shown to be superior due to their reduced OR time and EBL. As for the higher rate of pseudoarthrosis, this outcome may not be related to the cage numbers and it did not affect clinical outcomes. Nevertheless, one must consider other factors such as radiographic sagittal parameters before making a surgical decision.